With the development of the display technology, the dimension of display screen becomes increasingly larger. In addition to the capability of displaying one video signal with a large screen display, it is desired to show a plurality of video signals on such display simultaneously, which is also referred to as split-screen display.
Currently, the standardized video interfaces include Video Graphic Array (VGA), Digital Visual Interface (DVI), High Definition Multimedia (HDMI) and DisplayPort (DP, a digital display interface). Among these interfaces, the VGA, DVI and HDMI can only support one single display device on each data line, while the DP Specification 1.2 can support a multi-screen serial display function.
As shown in FIG. 1, a notebook computer, as a video signal source, is connected to external displays A, B, C and D. As shown, the display A is connected to the notebook computer directly and the displays B, C and D are connected in series to the display A. In this way, each display can be independently controlled to display different contents. These displays may be different from each other in terms of resolution and size. The DP 1.2 can support a bandwidth up to 5.4 Gbps per signal pair. That is, all these displays A, B, C and D can achieve a 1920*1080 full definition display at the same time and the bandwidth between the display A and the notebook computer host is the summed bandwidths occupied by the four displays, such that a display effect equivalent to parallel arrangement is possible.
FIG. 2 is a schematic diagram showing a parallel connection between several displays. As shown, a host Z is connected to displays E, F and G, respectively. The displays E, F and G are connected to the host Z via their respective video interfaces. For example, the display E can be connected to the host Z via interface 1, the display F can be connected to the host Z via interface 2, and the display G can be connected to the host Z via interface 3. The interfaces 1, 2 and 3 can be video interfaces or other type of interfaces. A host can be connected with several displays for improved efficiency. As an example, one display can be used for word processing, one or more displays for dynamical displaying information on stock market, and one display for instant messaging (such as MSN and QQ) or SKYPE voice. These displays will not interfere with each other.
However, both solutions suffer from the following disadvantages in common: an excessive number of displays occupy much space and have high costs. For example, some conventional applications such as web page browsing, office applications and games typically do not need high definition resolution. For such applications, a resolution of 1280*1024 will be sufficient, which is also a resolution used by most of applications. On the other hand, an instant messaging application such as MSN requires a very small screen space for which a resolution of 300*500 will be enough.
In implementation of the present invention, the inventors have realized at least the following problem in the prior art. In the prior art, it is not possible to perform a split-screen display in a single display device in such a manner that each screen can achieve the same function as one of the multiple displays as described above with respect to FIGS. 1 and 2.